1. Field of the Invention
The present invention relates to radio paging devices and more particularly to a radio paging receiver having a call reminder alert which periodically reminds the user that a paging signal has been received.
2. Description of the Prior Art
Radio paging devices are used in many applications to alert a user of a call. Such devices generally incorporate a radio receiver capable of producing an audible, alerting signal which can be heard by the user. Another type provides the additional feature of a voice message following the audible alert. These devices are referred to as tone only and as tone and voice pagers, respectively. To conserve battery life, many tone and voice pagers incorporate circuitry for limiting the length of both the alert tone signal and the voice message following the alerting signal. These paging receivers will electronically silence themselves after a specific period of time has succeeded the alert. Similarly, the tone only pagers will generally emit an alerting signal for only a limited period of time. Under these operating conditions, a user's pager might generate a paging alert, but the user may remain unaware of that alert because the paging device has electronically silenced itself. Thus, the user would never respond to the page. Two examples illustrative of the aforementioned situation are where the audible alert cannot be heard because of locally high ambient noise levels and where the user has momentarily left the paging device unattended.
To circumvent some of the above problems and to minimize the possibly disruptive effects of a paging alert at an inconvenient time or place, memory devices have been used to store a call which has been received so that an audible alert is not necessary. Such devices require the user to interrogate the pager memory at his convenience and, also, to initially place the paging device in the memory mode of operation. If the user can sufficiently anticipate where such circumstances may occur, the memory feature is desirable and the possibilty of a paging message eluding the user may be minimized. The memory feature, however, is particularly inconvenient if the user forgets that he has silenced the paging device by placing it in the memory mode and, additionally, the memory feature is ineffective if the circumstances which would cause an alerting signal to be overlooked are either transitory or unpredictable, or both.
A technique which has been utilized to effectively overcome these paging device limitations has been the use of a call light. A call light is often used in lieu of an alerting signal, or alternatively, in conjunction with the alert tone but remainson, or in a periodically flashing state, until the user discontinues it. Utilization of this feature requires that the paging device be in plain view of the user and that, like the memory feature, it be consciously checked by the user. With the paging device inside an article of clothing or on the waist this may not be a convenient operation. Furthermore, the high current drain of the alert light, which often flashes once a second, is not consistent with goals for maximizing the battery life.